Experimental Ebola Vaccine Will Be Put To Human Test

Scanning electron micrograph shows Ebola virus (red) on the surface of a kidney cell from an African green monkey.

NIAID

Originally published on September 4, 2014 3:18 pm

An Ebola vaccine being developed by the National Institutes of Health and drugmaker GlaxoSmithKline is going to get a try in healthy people starting next week.

The number of Ebola cases and deaths continues to climb in Western Africa, underscoring the need for a vaccine to protect people from infection. There's no such vaccine now.

"This is a public health emergency that demands an all-hands-on-deck response," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Thursday.

It's the first time the vaccine will be tested in humans. Animal experiments have been encouraging, but there's no guarantee the vaccine will work well in people. Several experimental vaccines against Ebola have been tested previously, but none has made it to the finish line.

The initial test of the new vaccine will involve 20 healthy volunteers and will take place at the NIH in Bethesda, Md. Similar tests are expected to involve 40 people in Mali, 40 in Gambia, 60 in the U.K. and possibly more in Nigeria down the road.

The preliminary studies aim to find out if the vaccine is safe and whether it triggers a strong immune response. Results are expected by the end of the year.

Vaccine testing is a "delicate balance," Fauci said. Researchers have to weigh "compassionate need" and the need to do what's "scientifically and ethically sound." Unlike a drug, a vaccine to prevent infection is given to otherwise healthy people. "Safety is paramount," he said.

Researchers are hopeful that this vaccine represents an improvement over previous approaches. The vaccine this time makes use of a chimpanzee cold virus, called chimp adenovirus type 3, to carry bits of genetic material derived from two kinds of Ebola: Ebola Zaire, the one at the center of the West African outbreak, and Ebola Sudan. Another version of the vaccine targets only Ebola Zaire.

Once the chimp virus is inside human cells, the Ebola gene leads the body to make Ebola protein to build immunity. There's no danger of Ebola infection or illness from the vaccine.

GlaxoSmithKline said it would make around 10,000 doses of vaccine beyond those used in the clinical tests so that an emergency supply would be available if the preliminary trials prove successful.

An experimental Ebola vaccine licensed to NewLink Genetics Corp. by the Public Health Agency of Canada is also expected to be tested in humans soon. Work on that vaccine is being backed by the Defense Department.